Stone exposed in the air or used for a period of time. It would be come out many phenomenas as follows:
Yellow spot, the rust spot, white phenomenon - white thing run off, oil spot, salt spot, coffee etc.

Pure method:

The physics washes and the chemistry washes are the common ways.

The physics washes is too expensive because it need the related equipments.So it often use chemistry method washes.
1 sour cleaning: hydrochloric acid, sulfuric acid, nitric acid, lemon acid,grass acid etc of the inorganic acid uses. But it almost not to use it. because the inorganic acid will remain a little acid. It bad for carbonate stone material, so it should use organic acid more.
2 alkali cleaning: It is main to acidities infectant.

Protection method

It doesn’t avoid to be dirty greasy and other phenomenon after being used.
How to maintain it?

Wash method: Wash with the neuter detergent and the soft things.

Protection method: It should use the high permeates protection to wash. This product can completely seep into the iner stone and clos the sligh hole, attain to prevent the infectant things into, and the most important is to use the surface protection at the last. It will be reach to the best protective effect.